Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C69/00—Esters of carboxylic acids; Esters of carbonic or haloformic acids
  • C07C69/34—Esters of acyclic saturated polycarboxylic acids having an esterified carboxyl group bound to an acyclic carbon atom
  • C07C69/44—Adipic acid esters
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C67/00—Preparation of carboxylic acid esters
  • C07C67/36—Preparation of carboxylic acid esters by reaction with carbon monoxide or formates
  • C07C67/38—Preparation of carboxylic acid esters by reaction with carbon monoxide or formates by addition to an unsaturated carbon-to-carbon bond

Definitions

• the present invention relates to the preparation of alkyl adipates by reacting carbon monoxide and an alcohol with particular admixture of alkyl pentenoates.
• an alkyl 3-pentenoate is prepared by reacting carbon monoxide and an alcohol with butadiene at high pressure and elevated temperature in the presence of cobalt carbonyl and of a heterocyclic nitrogenous base, for example pyridine.
• Exemplary such techniques include:
• a large fraction of the deactivated cobalt may be reactivated; a large fraction of the pyridine is thus removed from the carbonylation system (first and/or second stage).
• a large fraction of the pyridine is thus removed from the carbonylation system (first and/or second stage).
• a major object of the present invention is the provision of an improved process for the preparation of alkyl adipates by reacting carbon monoxide and an alcohol with an alkyl pentenoate, in which the chemical loss of the nitrogenous heterocyclic base is substantially reduced, while substantially maintaining the other performances of the reaction (activity, selectivity for adipate, etc.).
• the present invention features, in a first embodiment thereof, a process for the preparation of alkyl adipates by reacting carbon monoxide and an alcohol with an alkyl pentenoate at a pressure above atmospheric pressure and at an elevated temperature, in the presence of a catalytically effective amount of cobalt or a cobalt compound and of a nitrogenous heterocyclic base, said alkyl pentenoate comprising admixture consisting essentially of alkyl 3-pentenoate and 2-pentenoate.
• This invention also features a process for the preparation of alkyl adipates, comprising, in a first stage, converting butadiene, in known manner, into alkyl 3-pentenoate by reacting same with carbon monoxide and with an alcohol, at a pressure above atmospheric pressure and at elevated temperature, in the presence of a catalytically effective amount of a catalyst based on cobalt or palladium, and, in a second stage, reacting the pentenoate thus produced with carbon monoxide and an alcohol, also at a pressure above atmospheric pressure and at elevated temperature, in the presence of a catalytically effective amount of cobalt or of a cobalt compound and of a nitrogenous heterocyclic base, also in known manner, and which further comprises:
• a mixture consisting essentially of alkyl 3-pentenoate and alkyl 2-pentenoate is introduced into the so-called second stage reaction.
• Such mixture can, of course, also contain alkyl 4-pentenoate and various other constituents such as alkyl pentenoate, pyridine (or nitrogenous heterocyclic base), alkyl methylglutarate, one or more organic diluents and/or solvents, variable amounts of the catalyst system employed during the reaction stage by which the butadiene or mixture containing butadiene is converted into alkyl 3-pentenoate in known manner (first stage) whereby this catalyst system is compatible with the required reaction conditions for the second stage.
• first stage the reaction stage by which the butadiene or mixture containing butadiene is converted into alkyl 3-pentenoate in known manner (first stage) whereby this catalyst system is compatible with the required reaction conditions for the second stage.
• the alkyl pentenoates will constitute at least 20% by weight and, preferably, at least 40% by weight of the mixture introduced into the second stage.
• alkyl 2-pentenoate it is essential that alkyl 2-pentenoate be present in the mixture introduced into said second stage. Indeed, it has now been determined that this presence has a remarkable influence both on the production efficiency of the required alkyl adipate and on the chemical loss of nitrogenous heterocyclic base. These surprising effects are manifest as soon as the alkyl 2-pentenoate content in the mixture introduced (alkyl 3-pentenoate+2-pentenoate) constitutes at least 5% and preferably at least 10% thereof.
• this content will be at least 30%, the maximum being dictated merely by considerations of an economic nature and/or the availability of the alkyl 2-pentenoates.
• the alkyl 3-pentenoates obtained during the first stage can constitute on the order of 90% to 95% (by weight) of the identified products formed.
• it will thus be appropriate to enrich the raw material introduced into the second stage in said alkyl 2-pentenoates.
• a first technique of enriching said raw material in alkyl 2-pentenoate will include at least partial recycling of the alkyl 2-pentenoate formed in said second stage, in which the degree of conversion of the pentenoates will have been deliberately limited.
• a second technique of enriching the raw material in alkyl 2-pentenoate will comprise the preliminary treatment of all or a portion of the alkyl 3-pentenoate emanating from said first stage and/or not converted in the second stage, with a view to isomerizing same to a mixture enriched in alkyl 2-pentenoate, such mixture then being itself introduced into the second stage.
• the isomerization can be carried out in various ways which are per se known to the art and, in particular, via the process described in U.S. Pat. No. 4,339,597.
• the alkyl 3-pentenoate in the presence of cobalt or of a cobalt compound, if appropriate of carbon monoxide and/or of a nitrogenous heterocyclic base, at a temperature above or equal to 150° C., in liquid phase, at a pressure above atmospheric pressure, for a sufficient period of time as to obtain the desired enrichment.
• reaction temperature for such treatment will be less than or equal to 250° C. and will preferably range from 170° to 200° C.; the total pressure at temperature will be greater than or equal to 20 bar and preferably less than or equal to 300 bar.
• the treatment reaction mixture will in most instances be substantially free from alkanol and will be capable of including a nonpolar aprotic organic diluent or solvent.
• organic solvents useful for such treatment include unsaturated or, preferably, saturated acyclic hydrocarbons, aromatic hydrocarbons and ethers such as tetrahydrofuran and dioxane.
• the amount thereof When using a solvent or diluent, the amount thereof will be such that the weight content of the alkyl 3-pentenoate is at least 10% and, preferably, at least 50%.
• the presence of a nitrogenous heterocyclic base is not harmful so long as it is present in a minor amount, such that the N/Co ratio is less than or equal to 25.
• nitrogenous heterocyclic base as in the case of the first and second stages, compounds well known to this art are intended, notably those described more particularly in European Patent No. 80/0,957.
• Pyridine and isoquinoline are exemplary such compounds.
• duration of the treatment may vary over wide limits and will depend to a great extent on the precise nature of the catalyst system and on the other operating conditions selected (presence or otherwise of CO, pressure, temperature, etc.).
• the alkyl 3-pentenoate is contacted with carbon monoxide in the presence of a cobalt carbonyl, for example of dicobalt octacarbonyl.
• the carbon monoxide employed is substantially pure, advantageously in a form which is commercially available.
• the presence of a minor proportion of hydrogen ( ⁇ 1 vol %) tends to stabilize the catalyst system.
• a threshold on the order of 1% (vol) an interfering or competing hydrogenation reaction of the raw material is likely to occur at the expense of the desired isomerization reaction.
• reaction mixture will be substantially free from alkanol.
• the alkyl 3-pentenoate is treated in the presence of a cobalt carboxylate, for example cobalt acetate, and of a nitrogenous heterocyclic base, in the absence of carbon monoxide, the atomic ratio N/Co advantageously being selected such that it is compatible with proper progress of the second stage of the reaction and typically ranges from 2 to 25 (approximately).
• a cobalt carboxylate for example cobalt acetate
• nitrogenous heterocyclic base in the absence of carbon monoxide
• the reaction mixture may advantageously contain an alkanol.
• the cobalt concentration in the reaction mixture will be at least 0.05 mol/l and advantageously will range from 0.1 to 2 mol/l.
• the pressure is released and, if appropriate, the reaction mixture is cooled.
• the mixture thus obtained can be introduced directly, or after removal of the solvent or diluent, into the so-called "second stage" reaction, by which the alkyl adipate is produced in a manner known per se after adjusting the amount of the nitrogenous heterocyclic based, if appropriate of the cobalt concentration and the addition of an alkanol.
• carbon monoxide and an alcohol are reacted in liquid phase with the mixture essentially consisting of alkyl 3-pentenoate and 2-pentenoate in the presence of cobalt or of a cobalt compound and of a nitrogenous heterocyclic based;
• the reaction temperature typically ranges from 100° to 200° C. and preferably from 130° to 180° C.
• the total pressure at temperature is generally higher than 50 bar and preferably ranges from 100 to 300 bar.
• the cobalt concentration can vary over wide limits, for example from 0.05 to 8 mol/l, and preferably from 0.1 to 2 mol/l.
• the molar ratio of the nitrogenous heterocyclic base to the cobalt typically ranges from 0.5 to 50 and preferably from 2 to 25.
• a C 1 -C 4 alkanol and more particularly methanol is preferably employed.
• the mixture introduced into the second stage typically exhibits the following composition, by weight:
• the alkyl adipate is recovered by any appropriate means, for example, eliminating the cobalt from the reaction mixture followed by distillation of the products of reaction and, if appropriate, recycling the unreacted pentenic esters or by phase separation after addition of a nonpolar aprotic solvent followed by the treatment of the resulting two phases, in a manner per se known to this art.
• the Control Test (a) was carried out using methyl 3-pentenoate.
• the Control Test (b) was carried out using methyl 2-pentenoate.
• Examples 1 to 3 were carried out using a mixture of 3-pentenoate and 2-pentenoate, the 2-pentenoate content of which is reported in Table I below, in which the results obtained are also reported, with t indicating the time required for complete conversion of the pentenoate(s).
• reaction temperature was 170° C.
• pressure was 150 bar
• rate of stirring was 1,200 rev/min
• carbon monoxide inlet flow rate was 60 l/h (CNTP).
• Hastelloy® B2 The following reagents were charged into a 125-ml capacity autoclave made of Hastelloy® B2:
• the autoclave was closed, purged with argon 5 and heated to 200° C. with agitation (by shaking). After hours of reaction at this temperature, it was cooled. The reaction mass was withdrawn, diluted with methanol and analyzed by gas phase chromatography.
• This example illustrates an isomerization--alkoxycarbonylation sequencing.
• reaction mass contained, in particular,
• the autoclave was then closed, purged with carbon monoxide (3 ⁇ 10 bar) and then heated to 170° C. under 150 bar of CO containing 0.5 vol % of hydrogen!.
• the stirring rate was 1,200 rev/min.
• the carbon monoxide was introduced at a constant flow rate of 60 l/h (CNTP).
• reaction mass was then drawn off and analyzed by gas phase chromatography and ion exclusion liquid chromatography.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

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• 1991
  • 1991-11-21 FR FR9114605A patent/FR2684099B1/fr not_active Expired - Fee Related
• 1992
  • 1992-10-23 TW TW081108471A patent/TW234118B/zh active
  • 1992-11-05 ES ES92420397T patent/ES2084318T3/es not_active Expired - Lifetime
  • 1992-11-05 EP EP92420397A patent/EP0543739B1/fr not_active Expired - Lifetime
  • 1992-11-05 DE DE69208047T patent/DE69208047T2/de not_active Expired - Fee Related
  • 1992-11-19 SK SK3438-92A patent/SK343892A3/sk unknown
  • 1992-11-19 MX MX9206685A patent/MX9206685A/es unknown
  • 1992-11-19 CZ CS923438A patent/CZ343892A3/cs unknown
  • 1992-11-20 JP JP4333737A patent/JPH06128192A/ja active Pending
  • 1992-11-20 CN CN92113410A patent/CN1072676A/zh active Pending
  • 1992-11-20 CA CA002083463A patent/CA2083463A1/fr not_active Abandoned
  • 1992-11-21 KR KR1019920021960A patent/KR930009980A/ko not_active Application Discontinuation
• 1994
  • 1994-02-18 US US08/199,544 patent/US5670701A/en not_active Expired - Fee Related

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